Pull it. It is IMO, a week link in the system. Instead of being a safety warning device it is a safety hazard (particularly older units). Mine drained the MC during a 1000 mi road trip, the sensor never illuminted. After tearing out the PWDA in a gravel parking lot and reconnecting the lines with some unions from the local auto parts store it has been great for the past two years.
1970 SIIA 88, Sold
1996 Disco I, RIP